How to Control Surface Flatness of Double-Curved GRC Panels: Key Technologies and Practical Methods

Driven by the dual forces of contemporary architectural aesthetics and engineering technology, double-curved GRC panels have become the "artistic language" of landmark buildings with their unique curved expressiveness. However, controlling their surface flatness has always been a recognized technical challenge in the industry. As an industry leader with 28 years of deep expertise in the UHPC/GRC/GRG/GRP materials field, Qinglong Group, through full-chain technological innovation, has kept the flatness error of double-curved GRC panels within the stringent standard of ±2mm/m, providing reliable curved-surface solutions for 100+ landmark projects.

Flatness control of double-curved GRC panels is essentially a collaborative interplay between material properties and engineering precision. Compared with flat components, double-curved shapes face problems during curing such as uneven fiber distribution and concentrated shrinkage stress in cement-based materials, and traditional processes often cause defects such as wavy patterns and local depressions on panel surfaces. Relying on the R&D strength of its provincial engineering technology center, Qinglong Group has established a trinity control system of "materials-molds-construction", the core of which lies in the deep integration of materials science and digital technology.

Material Formulation Optimization: The Intrinsic Guarantee of Flatness for Double-Curved GRC Panels

As a professional GRC manufacturer, Qinglong knows well that material formulation is the foundation of flatness control. By adjusting the glass fiber content (6-8% by volume) and the particle gradation of cement-based materials, it developed a dedicated double-curved GRC formulation that raises the material's flexural strength to over 22MPa and keeps the elastic modulus stable at 30GPa, reducing deformation during forming at the source. It also introduced a composite modification technology combining nano silica fume and polypropylene fiber, lowering the peak hydration heat by 15% and effectively mitigating micro-cracks on panel surfaces caused by thermal stress. This technology has been granted a national invention patent (Patent No.: ZLXXXXXX).

Digital Mold Technology: A Revolution in Precision Control of Double-Curved GRC Panels

Traditional wooden or steel molds can hardly meet the precision requirements of double-curved surfaces. Qinglong pioneered the introduction of five-axis machining centers and the Rhino/Grasshopper parametric design platform, achieving digital machining with a mold surface precision of 0.1mm. Taking the Dongguan Women and Children's Activity Center project as an example, its double-curved GRC curtain wall panels adopted 3D scanning reverse modeling technology, keeping the deviation between the design model and the actual mold within 0.5mm. It also innovatively adopted an adjustable flexible mold system that compensates for material shrinkage through hydraulic fine-tuning devices, achieving 99.8% conformity between the formed double-curved GRC panels and the designed curved surfaces.

Construction and Installation Techniques: The Last Mile of Flatness for Double-Curved GRC Panels

Even a perfect precast component can fall short due to installation errors. As an enterprise holding a Grade II professional contracting qualification for building curtain wall engineering, Qinglong developed the "3D laser positioning + modular installation" method. In the Nanjing East Road Century Plaza renovation project, BIM-based pre-assembly combined with real-time on-site scanning comparison kept the installation positioning error of each double-curved GRC panel within 1mm. At the same time, an elastic connection joint design was adopted, allowing panels a micro-displacement of ±3mm under temperature changes, which ensures flatness while preventing stress damage. This method won the AALBORG WHITE Cup UHPC Construction Engineering Innovation Award.

From material R&D to engineering practice, the flatness control of double-curved GRC panels tests an enterprise's full-chain technical strength. Qinglong Group's 28 years of industry accumulation is reflected not only in its participation in drafting the Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Building (JGJ/T423-2018), but more importantly in translating the standard into implementable engineering solutions. For architects pursuing ultimate aesthetics, choosing a GRC manufacturer with capabilities in material R&D, digital manufacturing, and precision construction is the key to realizing the dream of double-curved architecture. As Qinglong's mission states, "Creating Beautiful Architecture"—every 0.1mm of progress in flatness control is a relentless pursuit of architectural art.